This application is a 371 National Stage Application of International Patent Application No. PCT/CH96/00409, filed on Nov. 18, 1996, that has priority benefit of Swiss Patent Application No. 03373/95, filed on Nov. 28, 1995.
The invention relates to a packaging container made from a cold formed composite, a process for its manufacture and the use thereof.
It is known to employ packaging means for the purpose of protecting e.g. pharmaceutical products, medical aids, diagnostic aids and other products which are sensitive to light, gas and/or moisture. Particularly suitable types of packaging are shaped forms of packaging made by stretching, stretch drawing, or deepening. In order to make packaging impermeable to light, gas and vapours, the material from which the packaging is made must have a barrier layer. A particularly suitable barrier layer may be e.g. a metal foil or metal strip. In practice, as the metal foil alone is not able to fulfil all of the requirements made of a packaging material, further layersxe2x80x94in particular layers of plasticxe2x80x94are applied to one or both sides of the metal foil. Such layers may e.g. be extrusion bonded or layers in the form of films of thermoplastics attached by means of adhesive agents. With such multi-layer laminates readily formable packaging materials are produced that can be processed further e.g. into the base parts of blister packs or other forms of packaging.
It has now been found that none of the laminates which have found use in practice exhibit sufficient flatness and/or stiffness for further processing after being shaped into packaging forms or parts such as the base part of packaging. It has also been found that laminates which exhibit inadequate flatness and/or stiffness, after shaping into parts for packaging such as base parts for blister packs or push-through packs, result in shaped parts that also exhibit inadequate flatness and/or stiffness. By flatness is meant here that the laminate exhibits a tendency to roll or parts formed out of the laminate are domed and e.g. do not lie uniformly on a flat surface, but instead are curved in a wavy, arched or dome-like manner.
The object of the present invention is therefore to propose a packaging container which is manufactured out of a composite and the packaging container exhibits a high degree of flatness and/or stiffness.
That objective is achieved by way of the invention in that the composite from which the packaging container or parts thereof is/are manufactured exhibits a layered structure containing:
a) a plastic film having a thickness of 10 xcexcm to 250 xcexcm,
b) a biaxially or uniaxially stretched film of the polyvinylchloride, polyolefin, polyamide or polyester type having a thickness of 10 to 100 xcexcm, or a biaxially or uniaxially stretched plastic laminate of two films of the polyvinylchloride, polyolefin, polyamide or polyester type each having a thickness of 10 to 50 xcexcm,
c) a metal foil having a thickness of 20 to 200 xcexcm,
and
a1) a plastic film having a thickness of 10 to 250 xcexcm,
and the packaging container exhibits a high degree of flatness and/or stiffness.
Usefully, according to the present invention packaging containers, or parts thereof, exhibit a laminate which features between layer
c), the metal foil having a thickness of 20 to 200 xcexcm,
and
a1) the plastic film having a thickness of 10 to 250 xcexcm,
a layer
b1) a biaxially or uniaxially stretched film of the polyvinylchloride, polyolefin, polyamide or polyester type having a thickness of 10 to 100 xcexcm, or a biaxially or uniaxially stretched plastic laminate of two films of the polyvinylchloride, polyolefin, polyamide or polyester type each having a thickness of 10 to 50 xcexcm.